Deadline driven content delivery

Abstract

Examples of the present invention present a method of controlling content delivery in a network. A global quality of experience measure, QoE max , is calculated based on the packet loss rate in the network. As packet loss rate varies as a result of congestion conditions in the network, so will QoE max . A server delivering content over the network will attempt to reach QoE max for the content in its respective session. Those sessions with a quality of experience, QoE, less than QoE max will have its packet dispatch rate increased, and those with a QoE higher than QoE max will reduce its packet dispatch rate, subject to any delivery deadlines associated with the session. If the delivery deadlines of the sessions can be met without exceeding QoE max , then all sessions will end up achieving QoE max . Since QoE max is only a function of packet loss rate that all sessions miming over the same shared network agree upon, all sessions should converge on the same QoE.

The invention claimed is: 
     
       1. A method of managing content delivery between a server and a client over a network, wherein the content comprises a plurality of segments, and each segment having an associated delivery deadline, said method comprising:
 (i) determining a minimum packet dispatch rate for the packets of each segment, based on the delivery deadline associated with each segment, the delivery deadline associated with each segment identifying a specified time by which the packets of that associated segment are to be delivered to the client; 
 (ii) transmitting the packets of a segment over the network at a packet dispatch rate at least equal to the minimum packet dispatch rate, and determining the resulting total packet loss rate in the network; 
 (iii) determining a global network quality of experience parameter based on the determined total packet loss rate in the network over a plurality of sessions; 
 (iv) determining a predicted quality of experience of a next segment of the plurality of segments to be transmitted; 
 (v) comparing the predicted quality of experience with the global network quality of experience; and 
 (vi) adjusting the packet dispatch rate for the next segment in dependence on the result of the comparing step, whilst maintaining the packet dispatch rate at the minimum packet dispatch rate or higher. 
 
     
     
       2. A method according to  claim 1 , wherein if the predicted quality of experience is less than the network quality of experience, then increasing the packet dispatch rate for the next segment. 
     
     
       3. A method according to  claim 1 , wherein if the predicted quality of experience is higher than the network quality of experience, then decreasing the packet dispatch rate for the next segment. 
     
     
       4. A method according to  claim 1 , wherein the delivery deadlines associated with each segment are provided by the client to the server. 
     
     
       5. A server for delivering content to client over a network, wherein the content comprises a plurality of segments, and each segment having an associated delivery deadline, said server comprising a processor and storage memory storing instructions which upon execution by the processor enable the server to at least be adapted to:
 determine a minimum packet dispatch rate for the packets of each segment, based on the delivery deadline associated with each segment, the delivery deadline associated with each segment identifying a specified time by which the packets of that associated segment are to be delivered to the client; 
 transmit the packets of a segment over the network at a packet dispatch rate at least equal to the minimum packet dispatch rate, and determining the resulting total packet loss rate in the network; 
 determine a global network quality of experience parameter based on the determined total packet loss rate in the network over a plurality of sessions; 
 determine a predicted quality of experience of a next segment of the plurality of segments to be transmitted; 
 compare the predicted quality of experience with the global network quality of experience; and 
 adjust the packet dispatch rate for the next segment in dependence on the result of the comparing step, whilst maintaining the packet dispatch rate at the minimum packet dispatch rate or higher. 
 
     
     
       6. The server according to  claim 5 , wherein if the predicted quality of experience is less than the network quality of experience, then the packet dispatch rate is increased by the server for the next segment. 
     
     
       7. The server according to  claim 5 , wherein if the predicted quality of experience is higher than the network quality of experience, then the packet dispatch rate is deceased by the server for the next segment. 
     
     
       8. The server according to  claim 5 , wherein the delivery deadlines associated with each segment are provided by the client to the server.